吴建新
,
江伯鸿
,
徐祖耀
金属学报
研究了母相平均晶粒尺寸和有序度对Cu-25.62Zn-3.97Al-0.0018B(wt-％)形状记忆合金热弹性马氏体相变点的影响。从相变热力学出发,得到马氏体相变点和晶粒尺寸的平方根的倒数成线性关系,并且随晶粒尺寸增大,马氏体相变点升高,与电阻法测得的结果符合很好。运用Landau理论,得到马氏体相变点和母相有序度的定量关系式,与X光衍射和电阻法试验的结果符合较好。求得试验用合金母相DO_3有序化的激活能约为46kJ/mol。
关键词:
Cu-Zn-Al合金
,
shape memory alloy
,
thermoelastic martensite
,
grain size
,
ordering degree
戴鹏
,
吴明在
,
宫晨利
稀有金属
doi:10.3969/j.issn.0258-7076.2009.06.006
采用不完全相变内耗(IF)测量法, 在Cu-Al-Ni-Mn-Ti合金马氏体相变中获得双内耗峰, 即低温内耗峰和高温内耗峰. 高温内耗峰主要出现在频率小于0.050 Hz的范围, 其位置对应于相对动力学模量的拐点位置; 高温内耗峰峰值在测量频率范围内与振动频率成反比关系, 满足经典的Belko和Delorme模型; 高温内耗峰具有明显的反常应变振幅效应, 其峰值随变温速率的增大而增大, 这些都说明高温内耗峰的形成与相转变量有关.
关键词:
热弹性马氏体
,
内耗
,
高温内耗峰
LI Yongsen JIN Yongbai YU Ronghai Institute of Metal research
,
Academia Sinica
,
Shenyang
,
China Associate Professor
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
Based on experimental study of the time dependence of the recoverable shape memory effect (SME)of shape memory alloys Ti50Ni50,Ti50Ni48Cu2 and Ti50Ni45Cu5 an empirical re- lationship between recoverable strain energy,U_r,and temperature,T.was derived as: U_r=U_o[1-exp(-mT_R~n)] where m—characteristic constant related to material,and n-shape-temperature sensitivity. The Johnson-Mehl-Aerami's phenomenological description of the time dependence of phase transformation was adopted to obtain a semiquantitative relationship associated with recoverable SME.between thermoelastic martensite transformation and temperature.This semiquantitative relationship is correspondent with the empirical expression.
关键词:
shape memory effect
,
null
,
null
,
null
WANG Mingpu
,
LIU Jinwen Central South University of Technology
,
Changsha
,
China Lecturer
,
Dept.of Materials Science and Engineering
,
Central South University of Technology
,
Changsha 410083
,
China
金属学报(英文版)
The stabilization of thermoelastic martensite in a rapidly solidified Cu-Zn-A1 alloy is be- lieved to be the process of disordering in atomic configuration during which the structure of martensite gradually transforms into N9R(b/a=1/3~(1/2))from M18R.This is dependent upon the intrinsic decomposition tendency of the martensite.
关键词:
Cu-Zn-Al alloy
,
null
,
null
,
null
N.C.Si
金属学报(英文版)
The effects of heat treatment on the Cu-Zn-Al shape memory alloys with mixed REwere researched with the help of X-ray diffraction and transmission electron micro-scope (TEM).The results show that the shape memory alloys with martensite can beproduced by adding mixed RE and heat treatment processes holding at 820C -880Cfor 15min,quenching into oil,aging at 150C for 15min,and then holding in waterat 50C for 10min.The alloys have the lowest transformation thermal hysteresis.Among the four experimental heat treatment processes the gradationally quenchingmakes the alloy have the highest transformation temperature and quenching into oilor water at room temperature makes the alloy have the largest thermal hysteresis.Mi-crostructure examination shows that aging at 2000C could destroy the substructuresin lathy martensites in the alloy and form a lot of dislocations,and aging at 250℃could cause the bainite transformation in the alloy.
关键词:
Cu-Zn-Al (RE)
,
null
,
null
,
null
WU Jianxin JIANG Bohong XU Zuyao (T.Y.Hsu) Shanghai Jiaotong University
,
Shanghai
,
China Associate Professor
,
Dept.of Materials Science and Engineering
,
Shanghai Jiaotong University
,
Shanghai
,
China
金属学报(英文版)
The effect of grain size and ordering of the parent phase on the critical points of thermoelastic martensitic transformation in Cu-25.62 Zn-3.97 Al-0.0018 B(wt-%)shape memory alloy has been investigated.Based on the thermodynamics of phase transformation,a linear rela- tionship between the starting temperature of martensitic transformation and the reciprocal of the square root of grain size is obtained,i.e.M_s temperature rises with increasing grain size. It shows a good agreement with the results of electric resistance measurement.Applying the Landau's theory,a quantitative relationship between M_s and the ordering parameter of the parent phase is set up,which is well confirmed by the results of X-ray diffraction and electric resistance measurement.The activation energy of the ordering process in the parent phase of the alloy is calculated to be 46 kJ/mol.
关键词:
Cu-Zu-Al
,
null
,
null
,
null
,
null
